Posted by Phil Pickering (208.46.229.203) on December 18, 2000 at 20:50:00:
Waffle time! I'm starting to think Greater now, also. I have to concur with Steve on the bill/head length ratio issue. Every photo of juvenile Lesser I was able to find shows an equal length, while the bill is clearly longer on this bird. In fact, there may be more of a difference than is apparent due to the crouched posture sloping the back of the neck, and elongating the head (at least at the point where I was measuring).
I do have the impression that Lesser average a bit longer in primary projection, but this is probably too slight to be useful as a mark. It just looks longer than typical for Greater here.
I should know that the appearance of the bill base and breast streaking might be lighting or photo/monitor effect dependant, or just plain variable enough to not be trustworthy as distinctive marks by themselves. The extent and size of the white notching in the tertials, coverts, etc. also seems to be variable in both species.
I wouldn't bet the farm on Greater either, but perhaps there are important reasons that experienced birders' first impressions are 'Greater'. These might be hard to pin down jizz-related features, but perhaps they should be given more weight in this case. Steve mentioned the thick bill base and tapered bill shape for one. Staring at this thing my impression is also that it seems to lack the proportionately large-eyed 'cute' look typical of Lesser, and seems a bit too chunky and barrel-chested for Lesser. More things to look at anyway.
Cheers,
Phil